Prenatal tobacco exposure (PTE) is the most common preventable risk for adverse developmental outcome, affecting more than 500,000 infants per year. PTE has been linked to an increased likelihood of ADHD and other childhood disruptive behavior disorders. Several studies have found externalizing behavior problems in tobacco-exposed (TE) children in early childhood, as young as 2-3 years of age (Day, 2000;Wakschlag, 2006a). Poor self-regulation (encompassing both executive control and emotion regulation) subserved by prefrontal systems likely underlies the development of externalizing behavior problems in childhood (Nigg &Casey, 2006), because PTE disrupts dopaminergic function that drives prefrontal neural systems, providing a link between PTE and externalizing symptomatology. The purpose of this exploratory R21 project is to characterize the impact of PTE on self-regulation and the relation to externalizing problem behaviors to better understand the pathways to later externalizing disorders. Self-regulatory abilities in young TE children will be investigated by following an existing NIDA-funded cohort whose prenatal tobacco exposure has been prospectively quantified and verified biochemically (DA014661). Children will be assessed at age 36 months, a point early in development when reliable and valid measures of executive control and emotion regulation are available (Carlson, 2005, 2007;Espy, in press;Kochanska 2000). To accurately and reliably measure executive control and emotion regulation, sophisticated latent variable models are used, where multiple, child-friendly tasks are selected as indices of each construct, and the common factor variance is determined to generate "purer" latent construct variables that are less influenced by extraneous sources of variability (Miyake, 2000). TE children will demonstrate deficits in self-regulation, compared to non-exposed peers, and a dose- response relation will be observed. Clinically-relevant problem behaviors are assessed with state-of-the-art multi-method tools, the BASC-2 and DB-DOS (Wakschlag, 2005) and will be related to PTE via self-regulatory skills. Possible interactions with parenting and home environment quality will be explored. These relations will be considered controlling for other risk factors, including prenatal alcohol exposure, maternal self-regulation, and postnatal environmental tobacco exposure. The findings from this exploratory R21 project will help to better determine the mechanisms that underlie problem behaviors in young children that will inform efforts to develop targeted preventive interventions and public health campaigns in the longer term. PUBLIC HEALTH RELEVANCE: Prenatal tobacco exposure (PTE) affects more than 500,000 infants per year, and has been linked to increased disruptive behavior in young children (Day, 2000;Wakschlag, 2006a). This project will examine the mechanisms underlying this link by examining self-regulation, or the ability to control behavior and emotions in prenatally tobacco-exposed and non-exposed preschool children. Understanding the specific deficits associated with PTE will drive development of targeted interventions for at-risk preschoolers, and improve public health efforts to assist women smokers to quit during pregnancy.